CHAPTER X 



UDDER-TUBERCULOSIS 



Infectious Organism 



The infectious organism is the tubercle bacillus, bacillus 

 tuberculosis. This bacillus is well known and therefore I 

 shall omit its description. 



I will mention, however, that this organism differs from 

 the preceding in that it is a strict parasite and therefore 

 its occurrence is confined to the animal host. It has a very- 

 great geographical distribution nevertheless. In Sweden 

 it is common in the southern and middle parts, but is less 

 frequently found in the north. 



When excreted from the body of the host in pathological 

 discharges it cannot multiply under common conditions as 

 a strict parasite. Although it does not form spores it does, 

 however, obstinately resist harmful external influences as 

 drying or mixing with other bacteria like those of putre- 

 faction, and it may live for a month in dark places and 

 retain its virulence. 



Transmission of the infectious organism does not de- 

 mand direct contact of one animal with another, but can 

 be brought about by objects like straw which have become 

 contaminated by pathologic discharges containing the tu- 

 bercle bacilli. Indirect transmission, indeed, seems to be 

 the most common. 



I have never inoculated a cow's udder with tubercle 

 bacilli, but with an experiment one could depend upon the 

 same conditions as those obtained in the experiment with 

 bacillus pyogenes, i.e., that the bacilli are taken up by the 

 leucocytes through which the milk becomes free from the 

 bacilli, and after one week, fourteen days or longer after 



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